JPWO2016189811A1 - Road information detection device and road information detection method - Google Patents

Abstract

Get road information with high accuracy regardless of weather and time. A road information detection device for acquiring road information by radiating a beam from a transmission antenna having variable directivity to a road sign having a plurality of flat portions, and having a radiation angle including an azimuth angle with respect to a front direction of the vehicle The transmission antenna is controlled so as to scan the beam by switching, and a transmission / reception circuit that receives the reflected wave reflected by the plurality of plane parts as a reflected wave signal, a vehicle and each plane part based on the reflected wave signal, A distance and a reflected wave intensity detecting unit for detecting the reflected wave intensity of each reflected wave reflected by each plane and each plane part, and a radiation angle detecting unit for detecting a beam emitting angle based on the reflected wave signal, A heat map is created based on the radiation angle of the beam, each distance, and the reflected wave intensity of each reflected wave, and the heat map is analyzed using the threshold value of the reflected wave intensity. Comprising a road information analysis unit for acquiring road information, the by.

Description

  The present disclosure relates to a road information detection apparatus, and more particularly, to a road information detection apparatus that can acquire road information based on a reflected wave intensity of a beam.

  Conventionally, road information has been acquired by a vehicle driver visually confirming a road sign or the like. However, since the driver visually confirms the road sign, the vehicle can be controlled only through the driver. Therefore, there has been a problem that road information cannot be used directly as data for controlling the running of the vehicle. In order to solve this problem, various techniques for driving a vehicle more safely and comfortably have been developed in recent years.

  For example, Patent Document 1 discloses a method of acquiring road information by receiving road information data transmitted by radio communication from a road sign by a receiver attached to a vehicle. Further, Patent Document 2 discloses a method for acquiring road information associated with a bar code formed by recognizing an image of a bar code formed on a road surface or a side wall surface of a road by a camera attached to the inside of the vehicle. Has been. In the future, these methods can be applied to an automatic driving technique in which a person boarding a vehicle automatically travels to the destination only by inputting the destination on the screen.

Japanese Utility Model Publication No. 1-1111400 JP 2000-67375 A

  However, the method of Patent Document 1 requires a means for transmitting road information data. Therefore, in order to introduce this method to major roads nationwide, there is a problem that a great deal of time and cost is required. Further, in the method of Patent Document 2, since the in-vehicle camera recognizes the barcode associated with the road information, there is a problem that the barcode is not correctly recognized at night, rainy weather, fog, and the like. Furthermore, when a bar code is used as a road sign, the road sign becomes very large, which causes a problem that the landscape is deteriorated.

  An object of the present disclosure is to solve these problems and provide a road information detection device and a road information detection method that can acquire road information with high accuracy regardless of the weather and time.

  A road information detection device according to the present disclosure is a road information detection device that acquires road information by radiating a beam from a transmission antenna having variable directivity to a road sign having a plurality of plane portions. The plurality of plane portions include a first plane portion where the beam is incident on the plane portion from a direction perpendicular to the plane portion, and a second plane portion where the beam is incident on the plane portion from a direction other than the perpendicular direction. The transmitting antenna is controlled to scan the beam by switching a radiation angle including an azimuth angle with respect to the front direction of the vehicle, and the reflected wave reflected by the plurality of planar portions is used as a reflected wave signal. Based on the transmission / reception circuit to be received and the reflected wave signal, the distance between the vehicle and each plane part and the reflected wave of each reflected wave reflected by each plane part A distance and reflected wave intensity detector for detecting degrees, a radiation angle detector for detecting a radiation angle of the beam based on the reflected wave signal, a radiation angle of the beam, the respective distances, and the respective reflections A road information analysis unit that obtains the road information by creating a heat map based on the reflected wave intensity of the wave and analyzing the heat map using a threshold value of the reflected wave intensity.

  According to the road information detection apparatus according to the present disclosure, road information can be acquired based on the reflected wave intensity of the beam, and therefore road information can be acquired with high accuracy regardless of the weather and time.

It is a block diagram showing an example of composition of a road information detection device concerning a 1st embodiment of this indication. It is a schematic diagram for demonstrating operation | movement of the road information detection apparatus of FIG. 1 based on 1st Embodiment of this indication. 3 is a graph showing a change in reflected wave intensity with respect to a distance from the vehicle 100 in FIG. 2 to each plane portion Wn of a road sign according to the first embodiment of the present disclosure. It is a figure showing an example of a heat map concerning a 1st embodiment of this indication. It is a schematic diagram for demonstrating operation | movement of the road information detection apparatus of FIG. 1 based on 2nd Embodiment of this indication. It is a graph which shows the change of the reflected wave intensity with respect to the distance from the vehicle 100 in FIG. 5 to each plane part Bn of the road sign according to the second embodiment of the present disclosure. It is a figure showing an example of a heat map concerning a 2nd embodiment of this indication. It is a block diagram showing an example of composition of a road information detection device concerning a 3rd embodiment of this indication. It is a side view of a road sign concerning a 3rd embodiment of this indication. It is a schematic diagram for _{demonstrating} the surface angle of each plane part _{Wi, j} of FIG. It is a schematic diagram for demonstrating operation | movement of the road information detection apparatus of FIG. 8 based on 3rd Embodiment of this indication.

  Embodiments according to the present disclosure will be described below with reference to the drawings. In the following embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.

  In the present disclosure, a road sign including a side wall or a signboard is composed of a plurality of plane portions, and each plane portion reflects a beam. Here, the reflected light intensity of the reflected wave reflected by the plane part is large for the beam incident from the vertical direction to the plane part. On the other hand, a beam incident from a direction other than the direction perpendicular to the plane part has a small reflected wave intensity of the reflected wave reflected by the plane part. The road information indicated by the road sign is read by making the beam incident on each plane portion from various angles and detecting the reflected wave intensity of the reflected wave reflected by each plane portion. This will be described in detail below.

First embodiment.
FIG. 1 is a block diagram illustrating a configuration example of a road information detection device according to the first embodiment of the present disclosure. In FIG. 1, a road information detection apparatus includes a transmission / reception circuit 1 attached to the left end in front of a vehicle, a radiation angle detection unit 2, a distance and reflected wave intensity detection unit 3, a road information analysis unit 4, and a display unit 5. Is provided. The road information detection apparatus acquires road information by emitting a beam to a road sign having a plurality of flat portions. Moreover, each plane part inclines with respect to the virtual plane orthogonal to a vehicle advancing direction so that the beam radiated | emitted from the transmission / reception circuit 1 may inject with respect to each plane part from various angles, respectively. Here, in the flat surface portion (first flat surface portion) having an inclination such that the beam radiated from the transmission / reception circuit 1 is incident on the flat surface portion from the vertical direction, the reflected wave of the reflected wave reflected by the flat surface portion. The strength is high. On the other hand, in the plane part (second plane part) having an inclination such that the beam emitted from the transmission / reception circuit 1 is incident on the plane part from a direction other than the vertical direction, the beam is reflected by the plane part. The reflected wave intensity of the reflected wave is low.

  The transmission / reception circuit 1 includes a transmission beamforming control unit 10, a pulse generation unit 11, a D / A conversion unit 12, a multiplier 13, a local oscillator 14, a high-pass filter (HPF) 15, and an amplification unit. A transmission amplifier 16, a transmission antenna 17, a reception antenna 18, a reception amplifier 19 as an amplification unit, a multiplier 20, a low-pass filter (LPF) 21, an A / D conversion unit 22, and a phase shifter 23. Here, the transmission / reception circuit 1 controls the transmission antenna 17 so as to scan the beam (radio signal) by switching the radiation angle including the azimuth angle with respect to the front direction of the vehicle. The reflected wave reflected by the unit is received as a reflected wave signal.

  The transmission beamforming control unit 10 generates a beam control signal BCS for controlling the directivity of the transmission antenna 17 and transmits the generated beam control signal BCS to the phase shifter 23. The beam control signal BCS controls the beam transmission operation by the transmission / reception circuit 1. Here, the scanned beam (radio signal) is, for example, a radar wave. The radar wave is an electromagnetic wave having a frequency in a millimeter wave band such as a frequency band of 76 GHz to 81 GHz. In addition, the transmission / reception circuit 1 may be configured by LiDAR, sonar, or the like in addition to the millimeter wave radar. The transmission / reception circuit 1 scans a beam by switching a radiation angle having an azimuth angle, and receives a reflected wave reflected by a plurality of plane portions as a reflected wave signal. Further, the transmission beamforming control unit 10 generates a pulse generation signal PGS for generating a modulation signal (for example, a PAM (pulse amplitude modulation) signal) for performing a predetermined encoding process on the baseband signal. The generated pulse generation signal PGS is transmitted to the pulse generation unit 11. The pulse generation unit 11 generates the modulation signal based on the pulse generation signal PGS and outputs the generated modulation signal to the D / A conversion unit 12. The D / A converter 12 converts the modulated signal into an analog signal as a baseband signal, and outputs the baseband signal (analog signal) to the multiplier 13. The multiplier 13 multiplies the baseband signal from the D / A converter 12 and the local signal having a predetermined frequency generated by the local oscillator 14 to generate a multiplication result signal, and the generated multiplication. The resulting signal is output to the HPF 15. The HPF 15 performs a high-pass filtering process on the multiplication result signal from the multiplier 13 to generate a radio signal, and outputs the generated radio signal to the transmission amplifier 16 via the phase shifter 23. The transmission amplifier 16 amplifies the voltage level of the radio signal to a predetermined voltage level, and outputs the amplified radio signal to the transmission antenna 17.

  Based on the beam control signal BCS, the transmission beam forming control unit 10 controls the phase shifter 23 so that the beam (radio signal) radiated from the transmission antenna 17 is radiated in the direction of a predetermined azimuth. Here, based on the beam control signal BCS, the transmission beam forming control unit 10 causes the transmission antenna 17 to direct the beam in a predetermined unit angle step in a counterclockwise direction with reference to the traveling direction A0 of the vehicle. The phase shifter 23 is controlled to transmit to Here, the azimuth angle is a rotation angle in the counterclockwise direction with reference to the vehicle traveling direction A0 (see FIG. 2).

  The transmission antenna 17 is an antenna that can electrically switch the radiation direction of the beam, and is a variable directivity antenna configured by, for example, a phased array antenna. The transmission antenna 17 scans the beam by switching the radiation direction of the beam based on the beam control signal BCS.

  The reception antenna 18 receives the reflected wave signal of the beam radiated from the transmission antenna 17 and outputs the received reflected wave signal to the reception amplifier 19. The reception amplifier 19 amplifies the voltage level of the reflected wave signal received by the reception antenna 18 to a predetermined voltage level, and outputs the amplified reception signal to the multiplier 20. The multiplier 20 generates a multiplication result signal by multiplying the reception signal and the above-described local signal, and outputs the generated multiplication result signal to the LPF 22. The LPF 22 demodulates the baseband signal by performing a low-pass filtering process on the multiplication result signal from the multiplier 20, and outputs the demodulated baseband signal to the A / D converter 22. The A / D converter 22 converts the baseband signal into a digital signal, and outputs the digitally converted baseband signal to the radiation angle detector 2 and the distance and reflected wave intensity detector 3.

  The distance and reflected wave intensity detector 3 detects and detects the distance between the vehicle and each plane part and the reflected wave intensity reflected by each plane part based on the digitally converted baseband signal. Each distance and each reflected wave intensity is output to the radiation angle detector 2. Here, the distance and reflected wave intensity detection unit 3 starts from the transmission antenna 17 radiating the beam until the reception antenna 18 receives the reflected wave in which the beam is strongly reflected at a predetermined reflectivity or higher by each plane unit. By calculating this time, the distance between the vehicle and each plane portion is detected. Further, the radiation angle detection unit 2 estimates the arrival direction of the reflected wave signal based on the phase difference of the reflected wave signal (digitally converted baseband signal) received by each receiving antenna 18. The radiation angle detector 2 uses the phase difference of the reflected wave signal and the beam control signal BCS to analyze the azimuth data of the beam (reflected wave) as the azimuth angle where the plane portion that strongly reflects the beam exists and to analyze road information Output to part 4. The arrival direction estimation method is, for example, a beam former method or a Capon method. Further, the radiation angle detector 2 outputs the distance data and the reflected wave intensity data acquired from the distance and reflected wave intensity detector 3 to the road information analyzer 4.

  The road information analysis unit 4 calculates a beat map based on the azimuth angle, distance, and reflected wave intensity detected by the radiation angle detecting unit 2 and the distance between the vehicle and each plane detected by the reflected wave intensity detecting unit 3 and the reflected wave intensity. The road information is acquired by analyzing the heat map created and using the threshold value of the reflected wave intensity. The display unit 5 displays the road information input from the road information analysis unit 4.

  The operation of the road information detection apparatus configured as described above will be described below.

  FIG. 2 is a schematic diagram for explaining the operation of the road information detection apparatus of FIG. FIG. 2 shows a road sign (side wall) indicating road information composed of a plurality (N bits) of digital data. That is, the road sign is composed of N plane portions W1 to WN. The plane part farthest from the vehicle 100 is the plane part W1, and the plane parts W2, W3, W4,..., WN are formed as the plane part W1 approaches the vehicle 100. The interval between the plane portions Wn (n = 1, 2, 3, 4,..., N) may be zero, for example, or may have a predetermined interval.

  When the vehicle 100 scans the beam with respect to the road sign at the measurement position 200, the plane portion W0 is positioned in parallel to the vehicle traveling direction A0. The distance D is a distance from the transmission antenna 17 to the plane portion W0. Further, the virtual surfaces Cn (n = 1, 2, 3, 4,..., N, N + 1) positioned in the direction perpendicular to the vehicle traveling direction A0 are positioned in parallel to each other at a predetermined interval. The road sign has N plane portions Wn between the virtual plane C (N + 1) and the virtual plane C1 that are located away from the transmission antenna 17 by the distance d1. Here, each plane portion Wn is inclined by a predetermined rotation angle, which will be described later, counterclockwise with respect to each virtual plane Cn, with the intersection of the extension line of the plane portion W0 and each virtual plane Cn as the center. In addition, when there is a gap between the flat portions Wn, the road sign is integrally formed from the flat portion W1 to the flat portion W0 by providing a connecting portion in the gap. For example, a coupling portion is provided in each of the gap between the plane portion W1 and the plane portion W2 and the gap between the plane portion W2 and the plane portion W3.

  The transmission / reception circuit 1 controls the transmission antenna 17 so as to radiate a beam at every constant angle θd in a range of 0 degrees to 90 degrees with respect to the vehicle traveling direction A0. That is, the transmission / reception circuit 1 emits a beam at a radiation angle including an azimuth angle θn (n = 1, 2, 3, 4,..., N) that is a rotation angle in a counterclockwise direction with respect to the vehicle traveling direction A0. Thus, the transmission antenna 17 is controlled. The azimuth angle θn is calculated by the following equation (1). Here, 0 degree <θn <90 degrees.

  As shown in FIG. 2, the plane portions W1, W2, W4,..., WN are virtual surfaces so that the reflected waves from the plane portions W1, W2, W4,. It inclines with respect to C1, C2, C4,. For example, the plane portions W1, W2, W4,..., WN are imaginary planes C1, W1, W2 such that the beam emitted from the vehicle 100 enters the plane portions W1, W2, W4,. .., CN are inclined with respect to C2, C4,..., CN by the same rotation angle as the azimuth angles θ1, θ2, θ4,. On the other hand, the flat surface portion W3 is inclined with respect to the virtual surface C3 so that the reflected wave from the flat surface portion W3 is reflected with less than a predetermined reflectance. For example, the plane portion W3 is inclined by a rotation angle of 90 degrees with respect to the virtual plane C3 so that the beam emitted from the vehicle 100 is incident from a direction other than the vertical direction with respect to the plane portion W3.

  An electromagnetic wave reflecting material such as metal is formed on the surface of each flat surface portion Wn. The road information analysis unit 4 generates digital data of a first value (for example, digital data of “1”) when the reflected wave intensity reflected by the plane part is equal to or greater than the threshold value, and is reflected by the plane part. When the reflected wave intensity to be applied is less than the threshold value, digital data of a second value (for example, “0” digital data) is generated. Here, when the beam radiated from the vehicle 100 is incident on the plane part (first plane part) from the vertical direction, the reflected wave intensity reflected by the plane part is equal to or greater than the threshold value. On the other hand, when the beam radiated from the vehicle 100 is incident from a direction other than the vertical direction with respect to the plane part (second plane part), the reflected wave intensity reflected by the plane part is less than the threshold value. Become.

  The beam radiated from the transmitting antenna 17 at the azimuth angle θ1 (radiation direction A1) is strongly reflected by the plane portion W1 away from the vehicle 100 by the distance L1. The beam radiated from the transmitting antenna 17 at the azimuth angle θ2 (radiation direction A2) is strongly reflected by the plane portion W2 that is separated from the vehicle 100 by the distance L2. The beam radiated from the transmitting antenna 17 at the azimuth angle θ3 (radiation direction A3) is weakly reflected by the plane portion W3. The beam radiated from the transmitting antenna 17 at the azimuth angle θ4 (radiation direction A4) is strongly reflected by the plane portion W4 that is separated from the vehicle 100 by the distance L4. The beam radiated from the transmitting antenna 17 at the azimuth angle θN (radiation direction AN) is strongly reflected by the plane portion WN separated from the vehicle 100 by the distance LN.

  FIG. 3 is a graph showing a change in reflected wave intensity with respect to the distance from the vehicle 100 to each plane portion Wn of the road sign in FIG. The reflected wave intensity at distances L1, L2, L4,..., LN (plane portions W1, W2, W4,..., WN) is equal to or greater than the threshold value Th. Further, the reflected wave intensity at the distance L3 (plane portion W3) is less than the threshold value Th. The reflected wave intensity at the distance D (planar portion W0) is maximized because the distance from the vehicle 100 to the planar portion is the shortest.

  Next, the operation of the road information analysis unit 4 will be described below. The road information analysis unit 4 creates a heat map based on the azimuth angle detected by the radiation angle detection unit 2 and the distance and reflected wave intensity detected by the reflected wave intensity detection unit 3, and calculates the reflected wave intensity. Road information is acquired by analyzing the heat map created using the threshold. First, in order to accurately acquire road information regardless of the travel position of the vehicle, the distance D at which the reflected wave intensity of the beam emitted at an azimuth angle of 90 degrees is maximized is determined. Next, the road information analysis unit 4 uses the value of the determined distance D to calculate the distance Ln for each azimuth angle θn (n = 1, 2, 3, 4,..., N) by the following equation (2). calculate.

  Next, the road information analysis unit 4 determines whether or not the reflected wave intensity at each distance Ln is greater than or equal to a threshold value Th. The road information analysis unit 4 generates digital data “1” when it is determined that the reflected wave intensity is equal to or greater than the threshold value Th, and when it is determined that the reflected wave intensity is less than the threshold value Th. Generates digital data of “0”.

  FIG. 4 is an example of a heat map according to the first embodiment of the present disclosure. Here, a heat map is shown in which the intensity of the reflected wave can be identified by color shading when the horizontal axis is the distance Ln and the vertical axis is the azimuth. Since the reflected wave intensity at the distances L1, L2, L4,..., LN (planar portions W1, W2, W4,..., WN) is equal to or greater than the threshold value Th, the road information analysis unit 4 performs digital data “1”. Is generated. Further, since the reflected wave intensity at the distance L3 (plane portion W3) is less than the threshold value Th, the road information analysis unit 4 generates digital data of “0”. Therefore, the road information analysis unit 4 generates N-bit digital data “1101... 1” based on the reflected wave intensity at the distances L1, L2, L3, L4,. Then, the road information analysis unit 4 outputs road information associated with the generated digital data to the display unit 5. The display unit 5 displays the road information input from the road information analysis unit 4. The threshold value Th can be freely set and changed. Therefore, the threshold value Th can be set to an appropriate value.

  According to the road information detection apparatus according to the first embodiment of the present disclosure described above, road information can be acquired with high accuracy regardless of the weather and time.

  Also, a fixed pattern may be inserted in advance in N-bit digital data. With this configuration, digital data indicating road information can be more appropriately identified.

Second embodiment.
FIG. 5 is a schematic diagram for explaining the operation of the road information detection apparatus of FIG. 1 according to the second embodiment of the present disclosure. FIG. 5 shows a road sign (signboard) indicating road information composed of a plurality (N bits) of digital data. That is, the road sign is composed of N plane portions B1 to BN. The plane portion orthogonal to the vehicle traveling direction D0 is the plane portion B0, and the plane portions B1, B2, B3, B4 extend from the plane portion B0 to the direction orthogonal to the vehicle traveling direction D0 (for example, the left side of the drawing). ..., BN is formed. The interval between the plane portions Bn (n = 1, 2, 3, 4,..., N) may be zero, for example, or may have a predetermined interval.

  When the vehicle 100 scans the beam with respect to the road sign at the measurement position 200, the plane portion B0 is orthogonal to the vehicle traveling direction A0. The distance T is a distance from the transmission antenna 17 to the plane portion W0. Further, the virtual surfaces En positioned parallel to the vehicle traveling direction D0 are positioned parallel to each other at a predetermined interval. The virtual plane E1 is located away from the transmitting antenna 17 by a distance d2. Here, between the virtual plane E1 and the virtual plane EN, the road sign has N plane portions Bn. Further, the flat surface portion Bn is inclined by a predetermined rotation angle in the counterclockwise direction with respect to the flat surface portion B0 with the intersection of the extending line of the flat surface portion B0 and each virtual surface En as the center. In addition, when there is a gap between the flat portions Bn, the road sign is integrally formed from the flat portion B1 to the flat portion BN by providing a connecting portion in the gap. For example, a coupling portion is provided in each of the gap between the plane portion B1 and the plane portion B2 and the gap between the plane portion B3 and the plane portion B4.

  The transmission / reception circuit 1 controls the transmission antenna 17 so as to radiate a beam at every constant angle θd in the range of 0 to 90 degrees with respect to the vehicle traveling direction D0. That is, the transmission / reception circuit 1 emits a beam at a radiation angle including an azimuth angle θn (n = 1, 2, 3, 4,..., N) that is a rotation angle in a counterclockwise direction with respect to the vehicle traveling direction A0. Thus, the transmission antenna 17 is controlled. The azimuth angle θn is calculated by the following equation (3). Here, 0 degree <θn <90 degrees.

  As shown in FIG. 5, the flat portions B1, B3, B4,..., BN are arranged so that the reflected waves from the flat portions B1, B3, B4,. Each tilts with respect to B0. For example, the plane portions B1, B3, B4,..., BN are applied to the plane portion B0 so that the beam emitted from the vehicle 100 is incident on the plane portions B1, B3, B4,. On the other hand, it is inclined by the same rotation angle as the azimuth angles θ1, θ3, θ4,. On the other hand, the flat surface portion B2 is inclined with respect to the flat surface portion B0 so that the reflected wave from the flat surface portion B2 is reflected with less than a predetermined reflectance. For example, the plane part B2 is not inclined with respect to the plane part B0 (the rotation angle is 0 degree) so that the beam radiated from the vehicle 100 is incident from a direction other than the vertical direction with respect to the plane part B2. .

  An electromagnetic wave reflecting material such as a metal is formed on the surface of each planar portion Bn. The road information analysis unit 4 generates digital data “1” when the reflected wave intensity reflected by the plane part is equal to or greater than the threshold value, and the reflected wave intensity reflected by the plane part is less than the threshold value. In some cases, digital data “0” is generated. Here, when the beam radiated from the vehicle 100 is incident on the plane portion from the vertical direction, the intensity of the reflected wave reflected by the plane portion is equal to or higher than the threshold value. On the other hand, when the beam radiated from the vehicle 100 is incident from a direction other than the vertical direction with respect to the plane portion, the reflected wave intensity reflected by the plane portion is less than the threshold value.

  The beam radiated from the transmitting antenna 17 at the azimuth angle θ1 (radiation direction D1) is strongly reflected by the plane portion B1 that is separated from the vehicle 100 by the distance L1. The beam radiated from the transmitting antenna 17 at the azimuth angle θ2 (radiation direction D2) is weakly reflected by the plane portion B2. The beam radiated from the transmitting antenna 17 at the azimuth angle θ3 (radiation direction D3) is strongly reflected by the plane portion B3 that is separated from the vehicle 100 by the distance L3. The beam radiated from the transmitting antenna 17 at the azimuth angle θ4 (radiation direction D4) is strongly reflected by the plane portion B4 that is separated from the vehicle 100 by the distance L4. The beam radiated from the transmitting antenna 17 at the azimuth angle θN (radiation direction DN) is strongly reflected by the plane portion BN separated from the vehicle 100 by the distance LN.

  FIG. 6 is a graph showing a change in reflected wave intensity with respect to the distance from the vehicle 100 in FIG. 5 to each plane portion Bn of the road sign according to the second embodiment of the present disclosure. The reflected wave intensity at distances L1, L3, L4,..., LN (plane portions B1, B3, W4,..., BN) is equal to or greater than a threshold value Th. Further, the reflected wave intensity at the distance L2 (plane portion B2) is less than the threshold value Th. Note that the reflected wave intensity at the distance T (planar portion B0) is maximized because the distance from the vehicle 100 to the planar portion is the shortest.

  Next, the operation of the road information analysis unit 4 will be described below. The road information analysis unit 4 creates a heat map based on the azimuth angle detected by the radiation angle detection unit 2 and the distance and reflected wave intensity detected by the reflected wave intensity detection unit 3, and calculates the reflected wave intensity. Road information is acquired by analyzing the heat map created using the threshold. First, a distance T at which the reflected wave intensity of a beam emitted at an azimuth angle of 0 degree is maximized is determined. Next, the road information analysis unit 4 uses the value of the determined distance T to calculate the distance Ln for each azimuth angle θn (n = 1, 2, 3, 4,..., N) by the following equation (4). calculate.

  Next, the road information analysis unit 4 determines whether or not the reflected wave intensity at each distance Ln is greater than or equal to a threshold value Th. The road information analysis unit 4 generates digital data “1” when it is determined that the reflected wave intensity is equal to or greater than the threshold value Th, and when it is determined that the reflected wave intensity is less than the threshold value Th. Generates digital data of “0”.

  FIG. 7 is an example of a heat map according to the second embodiment of the present disclosure. Here, a heat map is shown in which the intensity of the reflected wave can be identified by color shading when the horizontal axis is the distance Ln and the vertical axis is the azimuth. Since the reflected wave intensity at the distances L1, L3, L4,..., LN (plane portions B1, B3, B4,..., BN) is equal to or greater than the threshold value Th, the road information analysis unit 4 Is generated. Further, since the reflected wave intensity at the distance L2 (plane portion B2) is less than the threshold value Th, the road information analysis unit 4 generates digital data of “0”. Therefore, the road information analysis unit 4 generates N-bit digital data “1011... 1” based on the reflected wave intensity at the distances L1, L2, L3, L4,. Then, the road information analysis unit 4 outputs road information associated with the generated digital data to the display unit 5. The display unit 5 displays the road information input from the road information analysis unit 4. The threshold value Th can be freely set and changed. Therefore, the threshold value Th can be set to an appropriate value.

  According to the road information detection apparatus according to the second embodiment of the present disclosure described above, road information can be acquired with high accuracy regardless of the weather and time.

  Also, a fixed pattern may be inserted in advance in N-bit digital data. With this configuration, digital data indicating road information can be more appropriately identified.

Third embodiment.
FIG. 8 is a block diagram illustrating a configuration example of a road information detection device according to the third embodiment of the present disclosure. Compared with the road information detection apparatus of FIG. 1, the road information detection apparatus of FIG. 8 includes a transmission / reception circuit 1A instead of the transmission / reception circuit 1, and includes a radiation angle detection section 2A instead of the radiation angle detection section 2. Instead of the analysis unit 4, a road information analysis unit 4A is provided. Here, the transmission / reception circuit 1 emits a beam (radio signal) reflected on a plurality of flat surfaces including an azimuth angle with respect to the front direction of the vehicle and an elevation angle that is an upward rotation angle with respect to the ground on which the vehicle 100 travels. The transmission antenna 17 is controlled so as to scan the beam (radio signal) by switching the signal, and the reflected wave reflected by the plurality of plane portions is received as a reflected wave signal. The radiation angle detector 2A detects an azimuth angle and an elevation angle. The transmission / reception circuit 1A of FIG. 8 includes a transmission beam forming control unit 10A instead of the transmission beam forming control unit 10 as compared with the transmission / reception circuit 1 of FIG.

  The transmission beam forming control unit 10A controls the transmission antenna 17 so as to radiate a beam at a constant angle θd within a range of azimuth angles of 0 to 90 degrees with respect to the vehicle traveling direction. Further, the transmission beam forming control unit 10A controls the transmission antenna 17 so as to radiate a beam at every fixed angle φd within an elevation angle range of 0 to 90 degrees. The azimuth angle θi (i = 1, 2, 3, 4,..., N) and the elevation angle φj (j = 1, 2, 3, 4,..., M) are respectively expressed by the following equations (5). Here, 0 degrees <θi <90 degrees and 0 degrees <φj <90 degrees.

  The road information analysis unit 4A generates heat based on the azimuth and elevation angles detected by the radiation angle detector 2A, the distance between the vehicle and each plane detected by the reflected wave intensity detector 3, and the reflected wave intensity. Road information is acquired by creating a map and analyzing the heat map created using the threshold value of the reflected wave intensity.

  The operation of the road information detection apparatus configured as described above will be described below.

  FIG. 9 is a side view of a road sign according to the third embodiment of the present disclosure. The road sign in FIG. 9 is different from the road sign in FIG. 2 in that it further includes a plurality (M pieces) of flat portions in the vertical direction. That is, the road sign in FIG. 9 has (N × M) plane portions. Accordingly, FIG. 9 shows a road sign indicating road information composed of digital data of (N × M) bits.

FIG. 10 is a schematic diagram for explaining the surface angle of each planar portion _{Wi, j} in FIG. As shown in FIG. 10, each flat surface portion W _{i, j} is inclined by an azimuth angle θ _i (i = 1, 2, 3, 4,..., N) with respect to a plane perpendicular to the vehicle traveling direction. Is further inclined in the vertical direction by an elevation angle φ _j (j = 1, 2, 3, 4,..., M).

  FIG. 11 is a schematic diagram for explaining the operation of the road information detection device of FIG. 8 according to the third embodiment of the present disclosure. Here, when the beam radiated from the transmission / reception circuit 1A is incident at 90 degrees (vertical direction) with respect to the road sign of FIG. 9, the reflected wave intensity becomes maximum.

Next, the operation of the road information analysis unit 4A will be described below. The road information analysis unit 4A creates a heat map based on the azimuth angle and distance detected by the radiation angle detection unit 2 and the distance and reflected wave intensity detected by the reflected wave intensity detection unit 3, and the reflected wave intensity The road information is acquired by analyzing the heat map created using the threshold value. First, a distance D at which the reflected wave intensity of a beam emitted at an azimuth angle of 90 degrees and an elevation angle of 0 degrees is maximum is determined. Next, the road information analysis unit 4A uses the determined value of the distance D to determine the azimuth angle θ _i (i = 1, 2, 3, 4,..., N) and the elevation angle φ _j (j = 1, 2,3,4, ..., the distance _{L i} for each _{M), j} is calculated by the equation (6).

Next, the road information analysis unit 4A determines whether or not the reflected wave intensity at each distance L _{i, j} is equal to or greater than a threshold value Th. The road information analysis unit 4A generates digital data “1” when determining that the reflected wave intensity is equal to or greater than the threshold Th, and when determining that the reflected wave intensity is less than the threshold Th. Generates digital data of “0”. The road information analysis unit 4A generates N × M-bit digital data based on the reflected wave intensity at each distance L _{i, j} . Then, the road information analysis unit 4A outputs road information associated with the generated digital data to the display unit 5. The display unit 5 displays the road information input from the road information analysis unit 4.

  According to the road information detection apparatus according to the above embodiment, road information can be acquired with high accuracy regardless of the weather and time.

  Also, a fixed pattern may be inserted in advance into N × M bit digital data. With this configuration, digital data indicating road information can be more appropriately identified.

Modification 1
In the above-described road sign (signboard or wall), the plane portion (first plane portion) that strongly reflects the beam is designed so that the beam is incident on the plane portion from the vertical direction, and does not strongly reflect the beam. The part (second flat part) is designed so that the beam is incident from a direction other than the vertical direction with respect to the flat part. For this reason, the design of the plane portion that strongly reflects the beam is different from the design of the plane portion that does not strongly reflect the beam. In the first modification, the design of the plane portion that does not strongly reflect the beam and the beam that is strongly reflected are different. The flat part is designed in the same manner, and a radio wave absorber is provided (covered) on the flat part that strongly reflects the beam. The road information detection apparatus according to the first modification of the embodiment of the present disclosure performs the same operation as the road information detection apparatus according to the above-described embodiment, and can obtain the same effects. Furthermore, the modified example 1 is designed so that all the plane portions strongly reflect the beam as compared with the above-described embodiment, and the radio wave absorber is provided (covered) only on the plane portion that does not strongly reflect the beam. Road information can be easily changed. Therefore, in the first modification, road information can be changed without requiring a large-scale construction such as exchanging road signs.

Modification 2
The road sign (the road sign in FIGS. 2 and 5) is different from the design of the plane part (first plane part) that strongly reflects the beam and the design of the plane part (second plane part) that does not strongly reflect the beam. In this case, a radio wave absorber may be provided in a part of the flat portion that strongly reflects the beam. Thereby, the reflected wave intensity of the reflected wave reflected by the plane part (second plane part) that does not strongly reflect the beam is equal to the reflected wave intensity reflected by the plane part (first plane part) that strongly reflects the beam. It is lower than the reflected wave intensity and is higher than the reflected wave intensity of the reflected wave absorbed by the plane part (third plane part) provided with the radio wave absorber. Therefore, a first threshold value for detecting the reflection intensity reflected by the first plane part, a second threshold value for detecting the reflection intensity reflected by the second plane part, By setting, the road sign can indicate road information made up of digital data of the Nth power of 3. Therefore, the second modification can increase the amount of road information without requiring a large-scale construction such as exchanging road signs.

Modification 3
In the above-described embodiment, the road sign includes a plurality of plane portions indicating test patterns, and includes a failure determination unit at the subsequent stage of the road information analysis unit 4. The failure determination unit determines that the road information detection device has failed when digital data acquired from a road sign indicating digital data of a test pattern (for example, “010101” or the like) is different from the test pattern.

Modification 4
In the above-described embodiment, the road sign includes a plurality of plane portions indicating a regular pattern according to a protocol (rule), and includes a failure determination unit 50 at the subsequent stage of the road information analysis unit 4. The failure determination unit determines that the road information detection device has failed when the digital data acquired from the road sign indicating the digital data of the regular pattern according to the protocol is different from the regular pattern.

  As described above, the road information detection apparatus according to the first aspect acquires road information by radiating a beam from a transmission antenna having variable directivity to a road sign having a plurality of plane portions. In the road information detection device, the plurality of plane portions include a first plane portion where the beam is incident on the plane portion from a direction perpendicular to the plane portion, and the beam is incident from a direction other than the direction perpendicular to the plane portion. The transmitting antenna is controlled to scan the beam by switching a radiation angle including an azimuth angle with respect to the front direction of the vehicle, and the beam is reflected by the plurality of planar portions. A transmission / reception circuit that receives the reflected wave as a reflected wave signal, and a distance between the vehicle and each planar portion based on the reflected wave signal and that reflected by each planar portion A distance and a reflected wave intensity detector for detecting the reflected wave intensity of the reflected wave, a radiation angle detector for detecting a radiation angle of the beam based on the reflected wave signal, and a radiation angle of the beam, respectively A road from which the road information is obtained by creating a heat map based on the distance and the reflected wave intensity of each reflected wave and analyzing the heat map using a threshold value of the reflected wave intensity An information analysis unit.

  The road information detection apparatus according to a second aspect is the road information detection apparatus according to the first aspect, wherein the road information analysis unit generates digital data by analyzing the heat map, and Get linked road information.

  The road information detection device according to a third aspect is the road information detection device according to the second aspect, wherein the road information analysis unit has a first value when the reflected wave intensity is greater than or equal to the threshold value. If the reflected wave intensity is less than the threshold, digital data of the second value is generated.

  The road information detection apparatus according to a fourth aspect is the road information detection apparatus according to the first aspect, wherein the transmission / reception circuit generates a beam control signal for controlling the directivity of the transmission antenna. The transmitting antenna is controlled to scan the beam based on the beam control signal.

  A road information detection apparatus according to a fifth aspect is the road information detection apparatus according to the first aspect, wherein the radiation angle further includes an elevation angle that is an upward rotation angle with respect to a ground on which the vehicle travels. Including.

  The road information detection device according to a sixth aspect is the road information detection device according to the first aspect, wherein at least one of the plurality of flat portions is provided with a radio wave absorber.

  A road information detection method according to a seventh aspect is a road information detection method for a road information detection device that acquires road information by radiating a beam from a transmission antenna to a road sign having a plurality of flat portions. The plurality of plane portions include a first plane portion where the beam is incident on the plane portion from a direction perpendicular to the plane portion, and a second plane where the beam is incident on the plane portion from a direction other than the perpendicular direction. A step of scanning the beam by switching a radiation angle including an azimuth angle with respect to the front direction of the vehicle, and a step of receiving the reflected wave reflected by the plurality of plane portions as a reflected wave signal And a distance between the vehicle and each plane part and a reflected wave intensity of each reflected wave reflected by each plane part based on the reflected wave signal. And a step of detecting the radiation angle of the beam based on the reflected wave signal, and creating a heat map based on the radiation angle of the beam, the distance of the beam, and the reflected wave intensity of the reflected wave. And obtaining the road information by analyzing the heat map using a threshold value of reflected wave intensity.

  The road information detection method according to an eighth aspect is the road information detection method according to the seventh aspect, wherein the step of acquiring the road information generates digital data by analyzing the heat map, and the digital data Including obtaining road information associated with the.

  The road information detection method according to a ninth aspect is the road information detection method according to the eighth aspect, wherein the step of acquiring the road information includes a step in which the reflected wave intensity is equal to or greater than the threshold value. Generating digital data of a value, and generating digital data of a second value when the reflected wave intensity is less than the threshold value.

  The road information detection method according to a tenth aspect is the road information detection method according to the seventh aspect, wherein the plurality of plane portions include a plurality of plane portions indicating a test pattern, and the test pattern is acquired. The method further includes the step of determining a failure of the road information detection device.

  The road information detection method according to an eleventh aspect is the road information detection method according to the seventh aspect, wherein the plurality of plane portions include a plurality of plane portions showing a regular pattern according to a protocol, The method further includes the step of determining a failure of the road information detection device by acquiring a simple pattern.

  As described above in detail, according to the road information detection device according to the present disclosure, road information can be acquired based on the reflected wave intensity of the beam, so that road information can be acquired with high accuracy regardless of the weather and time. It becomes.

DESCRIPTION OF SYMBOLS 1,1A ... Transmission / reception circuit 2, 2A ... Radiation angle detection part 3 ... Distance and reflected wave intensity detection part 4, 4A ... Road information analysis part 5 ... Display part 11 ... Pulse generation part 12 ... D / A conversion part 13,20 ... multiplier 14 ... local oscillator 15 ... high-pass filter 16 ... transmitting amplifier 17 ... transmitting antenna 18 ... receiving antenna 19 ... receiving amplifier 21 ... low-pass filter 22 ... A / D converter

A road information detection apparatus according to the present disclosure is a road information detection apparatus that acquires road information by radiating a beam from a measurement position through a transmission antenna having variable directivity to a road sign having a plurality of plane portions. there, each of the plurality of flat portions, the said beam from the first planar portion and the measuring position where the beam is incident on vertical direction from the measurement position is incident in directions other than the vertical direction The transmission antenna is controlled so as to scan the beam by switching a radiation angle including an azimuth angle with respect to the front direction of the vehicle , and the beam is reflected by the plurality of planar portions. A transmission / reception circuit that receives the reflected wave as a reflected wave signal, and the distance between the vehicle and each planar portion and the respective planar portion based on the reflected wave signal. The distance and the reflected wave intensity detecting unit for detecting the respective reflected wave intensity of the reflected waves, on the basis of the reflected wave signal, and the radiation angle detector for detecting the radiation angle of the beam, the radiation angle of the beam The road information is acquired by creating a heat map based on the reflected wave intensity of each of the distances and the reflected waves, and analyzing the heat map using a threshold value of the reflected wave intensity A road information analysis unit.

As described above, the road information detection apparatus according to the first aspect emits a beam from a measurement position through a transmission antenna having variable directivity to a road sign having a plurality of plane portions, thereby obtaining road information. a road information detecting apparatus for acquiring, each of the plurality of flat portions, the beam is vertical from the first planar portion and the measuring position where the beam is incident on vertical direction from the measuring position A second planar portion that is incident in a direction other than the direction , and controls the transmitting antenna to scan the beam by switching a radiation angle including an azimuth angle with respect to a front direction of the vehicle , and the beam is A transmission / reception circuit that receives a reflected wave reflected by the plurality of planar portions as a reflected wave signal, and a distance between the vehicle and each planar portion based on the reflected wave signal And a distance and reflected wave intensity detection unit for detecting the reflected wave intensity of each reflected wave reflected by each plane unit, and a radiation angle detection unit for detecting the radiation angle of the beam based on the reflected wave signal And generating a heat map based on the radiation angle of each beam, each distance, and the reflected wave intensity of each reflected wave, and analyzing the heat map using a threshold value of the reflected wave intensity. And a road information analysis unit that acquires the road information.

The road information detection apparatus according to a fourth aspect is the road information detection apparatus according to the first aspect, wherein the transmission / reception circuit generates a beam control signal for controlling the directivity of the transmission antenna. the Bei example, based on the beam control signal, for controlling the transmission antennas so as to scan the beam.

A road information detection method according to a seventh aspect includes a road information detection device that acquires road information by radiating a beam from a measurement position through a transmission antenna having variable directivity to a road sign having a plurality of plane portions. a road information detecting method for each of said plurality of planar portions, the beam is vertical from the first planar portion and the measuring position where the beam is incident on vertical direction from the measuring position is any of the second planar portion that is incident in directions other than the direction, the steps of scanning said beam by switching the radiation angle containing the azimuth with respect to the front direction of the vehicle, the beam by the plurality of flat portions Receiving the reflected wave as a reflected wave signal, and based on the reflected wave signal, the distance between the vehicle and each plane part and each plane part. Detecting a reflected wave intensity of the reflected wave of each reflected, on the basis of the reflected wave signal, and detecting a radiation angle of the beam, the radiation angle of the beam, each of said distance, and each Generating a heat map based on the reflected wave intensity of the reflected wave, and obtaining the road information by analyzing the heat map using a threshold value of the reflected wave intensity.

Claims (11)

A road information detection device for acquiring road information by radiating a beam from a transmission antenna having variable directivity to a road sign having a plurality of plane portions,
The plurality of plane portions include a first plane portion where the beam is incident on the plane portion from a direction perpendicular to the plane portion, and a second plane portion where the beam is incident on the plane portion from a direction other than the perpendicular direction. Including
The transmitting antenna is controlled so as to scan the beam by switching a radiation angle including an azimuth angle with respect to the front direction of the vehicle, and the reflected wave reflected by the plurality of plane portions is received as a reflected wave signal. A transceiver circuit;
Based on the reflected wave signal, a distance and a reflected wave intensity detecting unit for detecting a distance between the vehicle and each planar part and a reflected wave intensity of each reflected wave reflected by each planar part;
Based on the reflected wave signal, a radiation angle detector for detecting the radiation angle of the beam, and creating a heat map based on the radiation angle of the beam, the distance of the beam, and the reflected wave intensity of the reflected wave And a road information analysis unit that acquires the road information by analyzing the heat map using a threshold value of reflected wave intensity.   The road information detection apparatus according to claim 1, wherein the road information analysis unit generates digital data by analyzing the heat map, and acquires road information associated with the digital data.   The road information analysis unit generates digital data of a first value when the reflected wave intensity is greater than or equal to the threshold value, and second data when the reflected wave intensity is less than the threshold value. The road information detection device according to claim 2, wherein digital data of the value of is generated. The transmission / reception circuit further includes a transmission beam forming control unit that generates a beam control signal for controlling the directivity of the transmission antenna,
The road information detection apparatus according to claim 1, wherein the transmission antenna is controlled to scan the beam based on the beam control signal.   The road information detection device according to claim 1, wherein the radiation angle further includes an elevation angle that is an upward rotation angle with respect to a ground on which the vehicle travels.   The road information detection apparatus according to claim 1, wherein a radio wave absorber is provided on at least one of the plurality of plane portions. A road information detection method for a road information detection device for acquiring road information by radiating a beam from a transmission antenna for a road sign having a plurality of plane portions,
The plurality of plane portions include a first plane portion where the beam is incident on the plane portion from a direction perpendicular to the plane portion, and a second plane portion where the beam is incident on the plane portion from a direction other than the perpendicular direction. Including
Scanning the beam by switching a radiation angle including an azimuth angle with respect to a front direction of the vehicle;
Receiving the reflected wave reflected by the plurality of plane portions as a reflected wave signal;
Detecting, based on the reflected wave signal, a distance between the vehicle and each planar portion and a reflected wave intensity of each reflected wave reflected by each planar portion;
Detecting a radiation angle of the beam based on the reflected wave signal; creating a heat map based on the radiation angle of the beam, the distance of the beam, and the reflected wave intensity of the reflected wave; Obtaining the road information by analyzing the heat map using a threshold value of wave intensity.   The road information detection method according to claim 7, wherein the step of acquiring the road information includes generating digital data by analyzing the heat map, and acquiring road information associated with the digital data.   The step of acquiring the road information generates digital data of a first value when the reflected wave intensity is greater than or equal to the threshold value, and when the reflected wave intensity is less than the threshold value, The road information detection method according to claim 8, comprising generating digital data having a value of two. The plurality of plane portions include a plurality of plane portions indicating a test pattern,
The road information detection method according to claim 7, further comprising: determining a failure of the road information detection device by acquiring the test pattern. The plurality of plane portions include a plurality of plane portions showing a regular pattern according to a protocol,
The road information detection method according to claim 7, further comprising determining a failure of the road information detection device by acquiring the regular pattern.